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Research On Radio Frequency Stealth Technology For Orthogonal Waveform MIMO Radar

Posted on:2016-02-28Degree:DoctorType:Dissertation
Country:ChinaCandidate:S W YangFull Text:PDF
GTID:1108330473456071Subject:Signal and Information Processing
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Multiple input multiple output(MIMO) radar array configuration has more flexibility compared to Phased Array Radar. As a consequence MIMO radar can form a wide-beam but keep a lower gain. By means of multiple beam reception and a longer Integration time, MIMO Rader still perform as well as traditional Phased Array Radar for target detection but it may offer a better Radio Frequency(RF) Stealth performance especially in the case of main-lobe interception. This thesis is focus on how to improve the RF Stealth performance of MIMO Radar, thus the main research contents are as follows:(1) The Low Probability of Intercept(LPI) performance of MIMO radar is compared with that of phased array radar via intercept factor. For the Intercepter with the ability to accumulate the radar signal pulse, the LPI performance of both kinds of radars are compared according to the ratio of quiet ranges which is a function of the subarray number of MIMO radar.(2) An algorithm of Radio Frequency Stealth for MIMO Radar in Searching ModeIn order to improve the viability of MIMO radar in electronic warfare, the relationship between radar parameters and its searching performance as well as the RF stealth performance is firstly analyzed. An RF stealth optimization model considering both the intercept factor and the searching frame period is formulated for MIMO radar in searching mode. Based on the above model, an optimization algorithm of RF stealth for MIMO radar in searching mode is introduced, where the sub-array number, signal duty cycle, dwell time and searching frame period are controlled adaptively to optimize the RF stealth performance under the constraints of detection performance and time resource of the system. Simulation results show that with RF stealth algorithm in searching mode, MIMO radar can achieve desired detection performance and obtain better RF stealth performance compared with traditional phased array radar.(3) An algorithm of RF Stealth for MIMO Radar in Tracking ModeTo enhance RF stealth capability, a target tracking algorithm for MIMO radar is proposed in this thesis. It is based on the RF stealth model which takes the number of sub-arrays, peak transmitted power of signal, beam dwell time and sampling period into consideration. Simulation results demonstrate that compared with adaptive sampling period algorithm, MIMO radar can offer better RF stealth performance with the proposed algorithm.(4) MIMO radar transmit beamforming approach for radio frequency stealthIn order to improve the RF stealth capability of MIMO radar, a transmit beamforming method is proposed in this paper. The transmitted signal on each element is a linear combination of multiple orthogonal waveforms, and each waveform can form a beam independently in the direction of a specific target. The spheroidal sequences-based method is utilized to form a wide null in the sector containing intercept receivers so as to decrease the intercepted power. Finally, some comparisons have been performed between MIMO radar with transmit beamformers and conventional MIMO radar. Simulation results demonstrate that the RF stealth performance of the proposed beamformer is superior to others. A transmit beamformer of MIMO radar with low sidelobe is proposed exploiting the Fourier series representation of transmit beam pattern. The transmit beam pattern with the proposed approach can focus the energy towards targets while greatly low the sidelobe which is benefit for improving the RF Stealth performance of MIMO radar.(5) An algorithm of RF Stealth for MIMO radar conducting Multi-Target Tracking(MTT)We also study the MIMO radar which conducts MTT by collecting measurements on the group of tracks with single beam. A model based on RF stealth is proposed in which the mean signal-to-noise ratio of radar signal received by interceptor is minimized. Two kinds of constraints on signal to noise ratio of the echoes are introduced. The genetic algorithm is utilized to obtain optimal parameters which would lead to a better RF stealth performance.(6) anti-TDOA positioning capability for the orthogonal MIMO RadarTime delay estimation by the cross-correlation between signals received by two receivers in different directions relative to MIMO radar is analyzed. The impacts of reconnaissance receivers direction angle correspond to the radar antenna, signal frequency interval, single signal bandwidth on time delay estimation deviation of received orthogonal Stepped Frequency Division Linear Frequency Modulation(SFDLFM) MIMO radar signals, as well as phase coded signals, are discussed. The discussion proved, in theory, the anti-TDOA locating capability of those two kinds of waveforms. Finally, the theoretical analysis is verified by the simulation results. The results can be used as a reference for designing the signals with anti-TDOA capability.
Keywords/Search Tags:multiple-input multiple-out(MIMO) radar, radio frequency(RF) stealth, low probability of interception(LPI), target search, target tracking, beamforming, anti-position
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